Various versions are known of fire protection installations of the type described above. It is typically the case, however, that the known technology for fire protection has not been developed significantly in recent decades. There are today several different fire protection systems intended for either permanent, that is essentially unchangeable, installation in a particular environment or construction, such as, for example, fixed sprinkler installations in buildings, ships, machines, etc, or fire protection systems intended for mobile use from a temporary storage location once a fire has been detected, for example hand-held fire extinguishers, fire engines, etc. The fixed fire protection installations are very expensive, complicated and, in addition, difficult to modify when the risk environment is changed, while the mobile fire protection systems have, of course, the serious disadvantage that they are not in place when fire extinguishing is required.
The known fire protection systems utilize several different extinguishing mediums, such as powder, foam, liquid (usually water) and inert gas (usually CO2 or halon). Physical extinguishing principles are accordingly cooling, wetting or reduction of oxygen. Common to the three of these extinguishing mediums that are mentioned first is that they often cause great damage with consequently high costs for cleaning up. The use of gas as the extinguishing medium involves instead other special risks, as the fire is extinguished by the oxygen content being greatly reduced. This extinguishing medium is therefore not suitable for use in premises that are inhabited, other than only temporarily, by people or animals.
The present invention focuses primarily on liquid as the extinguishing medium and technically the fire extinguishing is essentially carried out by a cooling down of any combustion gases and a cooling down and wetting of the seats of fire by means of the said extinguishing liquid. In most cases, ordinary drinking water is the extinguishing liquid that is the best choice, as water does not have effects that are harmful to health. Other types of extinguishing liquid can, however, be used.
In currently-known fire protection systems based on liquid, in both stationary and mobile systems, it is common for the extinguishing liquid to be sprayed out at a relatively low pressure and with a very large flow, which always leads to the unwanted above-mentioned considerable damage and high clearing-up costs. Such fire protection systems can consist of, for example, units that are permanent or that are ready for use comprising water hoses, fixed water sprinklers, hand-held manual fire extinguishers containing liquid, etc.
In order to avoid these disadvantages, this invention utilizes instead the special technique of spraying out the liquid at a higher pressure through a special mist-spraying nozzle in order, in this way, to create a mist consisting of large quantities of small drops of liquid, which mist fills the surrounding space. The mist thereby cools combustion gases and seats of fire both more rapidly and more effectively than is the case with the abovementioned known fire protection systems based on a large flow of liquid, while at the same time a limited quantity of liquid solely in the form of mist results in no, or little, secondary damage from the extinguishing liquid. The physical extinguishing principles for mist can be divided into:                cooling of seats of fire, where the mist absorbs large amounts of heat when it is heated up and changes from liquid (water) to gas (steam).        prevention of heat radiation as the mist effectively absorbs IR-radiation.        displacement of oxygen when the mist changes from liquid to gas.        
Often the three principles apply at the same time and can be difficult to distinguish.
The National Swedish Institute for Materials Testing has carried out comprehensive tests on mist as an extinguishing medium and has found that the fire-fighting properties of water, particularly when it is in the form of mist, are very good, as it is possible to achieve the same or better extinguishing effect with a fraction of the quantity of water in comparison with traditional fire-extinguishing equipment that uses water. The said extinguishing effect is determined principally by factors such as the size and velocity of the drops of water and the aerodynamics surrounding the fire protection installation and along the enclosing surfaces of the object to be protected, preferably its ceiling. These factors affect, for example, the range of the mist, its rate of spread, penetrating properties and cooling properties.
That is, with a higher pressure and with the correct nozzle, it is possible to produce and spread a mist that provides much more effective extinguishing with a considerably smaller quantity of liquid, which results in significantly less damage in total in the event of a fire and, in addition, little or no water damage to clear up after the fire extinguishing has been carried out.
The mist technique is currently used for fire protection in fixed sprinkler installations on, for example, ships and in engine compartments in working vehicles. These installations are, however, at least as expensive as ordinary water sprinklers and often more difficult to install in existing constructions. This applies in particular in those constructions and installations where special attention must be paid to the nature of the object to be protected, for example in computer installations, listed buildings, homes for the elderly, etc. In addition, it is obvious that if changes are carried out to the internal structure of the object to be protected, for example a new installation that must be protected against fire, internal walls in new locations, etc, this is both difficult and expensive to carry out in a fixed system.
New requirements imposed by customers and by the authorities concerning fire protection in different environments demand an improved fire protection system that is both easier to install and that, in addition, is more effective. An initial risk group is residential environments for elderly people with reduced functionality and/or residential environments for people with physical, mental and/or social handicaps.
In these environments, the risk of fire is considerably greater. This risk group is also significantly over-represented when it is a question of injuries or deaths resulting from fires, often as a consequence of difficulties in escaping.
The number of deaths in fires amounts to approximately 150 per year in Sweden, with at least 50% of these being represented by the abovementioned risk group. This risk group includes, for example, people with dementia. According to statistics from the National Swedish Institute for Public Health, 6% of the population over the age of 65 are in this group, which means approximately 90,000 people. It is estimated that 20% of this risk group has an acute need for improved fire protection. The statistics are also representative of other Nordic countries.
In Norway, it has been found from fire statistics that the risk of elderly people dying in association with a fire is four times greater. Most of the deaths occur in the home, where fire protection is often non-existent, which in most cases also applies to those living in institutions. The study covered 253 municipalities and was very disheartening. Fire safety was found to be insufficient in 79% of a total of 2,312 municipal homes for the elderly, in which 24,250 elderly and handicapped people were living. Just the group with documented dementia that live at home is calculated to amount to approximately 30,000 people, and this number is constantly increasing. Norway calculates that safety measures in the form of fire alarms and fixed sprinkler systems will currently require investment amounting to well over NOK 300 million. It has also been found that active fire protection needs to be installed urgently in approximately 12,000 homes (by active fire protection is meant various types of sprinkler system). As a result, there is great interest in new and cheaper types of fire protection.
Another very great problem is that this risk group is rapidly increasing in number at a time when efforts are being made to enable the elderly and/or handicapped to remain in their ordinary home environment as long as possible, even those who are suffering from both physical and social handicaps. At the same time, the average age of the population is increasing, which means that the number of people in this category is increasing rapidly.
When new homes and institutions for the elderly are built today, they are subject to high demands relating to fire safety, both concerning the building techniques and technical protection systems. For already-existing residential environments of this type, the possible safety measures are, however, very limited, due to the lack of suitable fire protection systems and for reasons connected with cost. The installation of traditional fixed fire protection systems (that is sprinkler systems) in an existing building usually requires considerable changes to the property, which makes these solutions both difficult and expensive. Many of the existing fire protection systems have activation principles that are not dimensioned or designed to save lives, but are primarily designed to protect property.
In other words, society and to a great extent the local authorities and property owners are currently facing a huge problem that is both technical and economical when they attempt to find solutions that provide safety for these groups. This is not just a national problem, but is being faced throughout the whole of Western Europe as a consequence of social developments.
Another problematical risk environment is cultural heritage environments of different types, as these can range from small objects to be protected, ancient buildings and irreplaceable museums to whole areas of cities, which, in general, have very poor fire protection and are very difficult to tackle in the event of a fire. Making changes in such buildings is made more difficult by cultural heritage preservation legislation as this requires all changes to be made in such a way that the least possible damage is caused to the object and in such a way that any changes can be restored to the original state. A fixed sprinkler installation is therefore impossible or very difficult to install and, in addition, a fire extinguishing system based on a large flow of water usually results in considerable water damage while at the same time evacuation is hampered by the flow of water, for which reason fire protection installations based on a flow of liquid are unsuitable or are prohibited in cultural heritage premises, premises where expensive or sensitive items are stored or in premises where people and animals reside permanently.
According to the Nordic Safety Authorities, there are currently no fire protection systems commercially available on the market with the required function profile. All the currently known fire protection systems are either designed for manual use or else have one or more other disadvantages, such as, for example, they require complicated and/or expensive permanent installation, they hamper evacuation in the event of a fire, they have too small a capacity in relation to the volume of the room, their operating profile does not correspond to the necessary response time (that is the time that is required for the fire brigade to be able to start putting out the fire), they are not able to actively adapt the fire extinguishing measures that are carried out in response to the current situation and actual development of the fire, they require considerable maintenance and inspection in order to be reliable and, not least, they are very obtrusive and therefore clearly unsuitable in important cultural heritage environments.
There is consequently a great need for a cost-effective, portable, modular, actively detecting, temporary fire protection installation, in which modules can be selected taking into account the relevant risk environment and corrective measures can be carried out in response to the development of the fire, which temporary fire protection installation has a sufficient capacity to control, suppress or preferably extinguish a fire that has arisen, prior to normal fire-fighting activity being carried out, and which fire protection installation is able to be modified simply and at little cost when there are changes to the risk environment in which the fire protection installation is located.